That's the case with every pseudorandom number generator (ie any deterministic algorithm that spews "random" numbers). The period here is unusually short, but

That's the case with every pseudorandom number generator (ie any deterministic algorithm that spews "random" numbers). The period here is unusually short, but it is enough for the use case. If you want a non-predictable random bit source, you have to sample a quantum phenomenon using dedicated hardware.